Draft Research Plan
Draft Research Plan for Vitamin D Deficiency in Adults: Screening
This opportunity for public comment expired on November 21, 2018 at 8:00 PM EST
Note: This is a Draft Research Plan. This draft is distributed solely for the purpose of receiving public input. It has not been disseminated otherwise by the USPSTF. The final Research Plan will be used to guide a systematic review of the evidence by researchers at an Evidence-based Practice Center. The resulting Evidence Review will form the basis of the USPSTF Recommendation Statement on this topic.
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
Draft: Proposed Key Questions to Be Systematically Reviewed
1. a. Does screening for vitamin D deficiency result in improved health outcomes?
b. Does screening efficacy vary among patient subpopulations at higher risk for vitamin D deficiency (e.g., persons residing in institutions, with obesity, with low levels of sun exposure, or who are older)?
2. What are the harms of screening for vitamin D deficiency?
3. a. Does treatment of vitamin D deficiency with vitamin D result in improved health outcomes?
b. Does treatment efficacy vary among patient subpopulations at higher risk for vitamin D deficiency (e.g., persons residing in institutions, with obesity, with low levels of sun exposure, or who are older)?
4. a. What are the harms of treatment of vitamin D deficiency with vitamin D?
b. Do harms vary among patient subpopulations at higher risk for vitamin D deficiency (e.g., persons residing in institutions, with obesity, with low levels of sun exposure, or who are older)?
Draft: Proposed Contextual Questions
Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.
- What are the various assays for measuring serum vitamin D (including total and free 25-hydroxyvitamin D and 1,25-dihydroxycholecalciferol), and what is known about the intermethod and interlaboratory variability of these assays?
- In observational studies, what is the association between vitamin D use or serum vitamin D levels and selected health outcomes (i.e., mortality, fractures, falls, cardiovascular disease, and cancer)?
- What is the relationship between vitamin D use and selected intermediate outcomes (i.e., bone mineral density, blood pressure, and measures of physical or muscle strength)?
Draft: Proposed Research Approach
The Proposed Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Report. Criteria are overarching as well as specific to each of the KQs.
|Population||KQs 1, 2: Nonpregnant adults age ≥18 years without known vitamin D deficiency
KQs 3, 4: Nonpregnant adults enrolled in studies based on vitamin D deficiency (defined as serum vitamin D levels <30 ng/mL); studies in which 90% of the study population have serum vitamin D levels in the deficiency range will also be included
|Intervention||KQs 1, 2: Screening with serum 25-hydroxyvitamin D assay
KQs 3, 4: Treatment with oral or injectable vitamin D2 or D3, with or without calcium
|KQs 1, 2: Vitamin D−binding protein; 1,25-dihydroxycholecalciferol assay
KQs 3, 4: Food-based interventions; vitamin D analogs, multivitamins that include a vitamin D component, sun, or ultraviolet exposure
|Comparison||KQs 1, 2: No screening
KQs 3, 4: Placebo or no treatment, or usual care
|KQs 1, 2: Head-to-head comparisons of different serum vitamin D assays
KQs 3, 4: Head-to-head comparisons of vitamin D doses or formulations
|Outcomes||KQs 1, 3:
KQ 2: Anxiety and labeling
KQ 4: Toxicity, renal harms (e.g., nephrolithiasis), and other adverse events
|KQs 1, 3: Changes in serum vitamin D levels, intermediate physiologic outcomes (bone mineral density, osteoporosis, blood pressure, cholesterol, glucose, muscle mass), behavioral outcomes (changes in diet or physical activity), or physical fitness/muscle strength measures (e.g., grip strength, timed up and go test, distance walked test, step test, balance test)
KQs 2, 4: None
|Timing||KQ 1: Outcomes measured at 8 weeks or longer after screening
KQs 2, 4: Any duration and any timing of measurement
KQ 3: Duration of treatment intervention of at least 8 weeks; outcomes measured at 8 weeks or longer after start of treatment
|KQ 1: Outcomes measured at less than 8 weeks after screening
KQs 2, 4: None
KQ 3: Duration of treatment intervention of less than 8 weeks or outcomes measured at less than 8 weeks after start of treatment
||Countries categorized as less than “very high” on the Human Development Index|
|Study design||KQs 1, 3: CCTs, RCTs, and nested case-control studies within RCTs; systematic reviews of CCTs or RCTs with a similar scope to this review
KQs 2, 4: CCTs, RCTs, cohort studies, case-control studies, and systematic reviews with a similar scope to this review
|Editorials, narrative reviews, letters to the editor, and study designs not listed as specifically included (e.g., case reports, case series, studies without a comparison group)|
|Language||English language||Languages other than English|
|Study quality||Good- and fair-quality studies (i.e., studies with low risk of bias or some concerns for bias)||Poor-quality studies (i.e., studies with high risk of bias)|
Abbreviations: CCT=controlled clinical trial; RCT=randomized, controlled trial.
Internet Citation: Draft Research Plan: Vitamin D Deficiency in Adults: Screening. U.S. Preventive Services Task Force. October 2018.